Heart valves, such as the mitral, tricuspid, aortic, and pulmonary valves, are sometimes damaged by disease or by aging, resulting in problems with the proper functioning of the valve. Heart valve problems generally take one of two forms: stenosis in which a valve does not open completely or the opening is too small, resulting in restricted blood flow; or insufficiency in which blood leaks backward across a valve when it should be closed.
Heart valve replacement has become a routine surgical procedure for patients suffering from valve regurgitation or stenotic calcification of the leaflets. Conventionally, the vast majority of valve replacements entail full stenotomy in placing the patient on cardiopulmonary bypass. Traditional open surgery inflicts significant patient trauma and discomfort, requires extensive recuperation times, and may result in life-threatening complications.
To address these concerns, within the last decade, efforts have been made to perform cardiac valve replacements using minimally-invasive techniques. In these methods, laparoscopic instruments are employed to make small openings through the patient's ribs to provide access to the heart. While considerable effort has been devoted to such techniques, widespread acceptance has been limited by the clinician's ability to access only certain regions of the heart using laparoscopic instruments.
Still other efforts have been focused upon percutaneous transcatheter (or transluminal) delivery of replacement cardiac valves to solve the problems presented by traditional open surgery and minimally-invasive surgical methods. In such methods, a valve prosthesis is compacted for delivery in a catheter and then advanced, for example through an opening in the femoral artery and through the descending aorta to the heart, where the prosthesis is then deployed in the valve annulus (e.g., the aortic valve annulus).
Valve prostheses are generally formed by attaching a bioprosthetic valve to a frame made of a wire or a network of wires. Such a valve prosthesis can be contracted radially to introduce the valve prosthesis into the body of the patient percutaneously through a catheter. The valve prosthesis can be deployed by radially expanding it once positioned at the desired target site. The valve prosthesis is mounted onto a distal tip of the catheter assembly prior to delivery to the target location where the valve prosthesis is expanded into place.
To prepare such a valve prosthesis for implantation, the valve prosthesis can be initially provided in an expanded or uncrimped condition, then crimped or compressed around the distal tip of the catheter assembly until the valve prosthesis is as close to the diameter of the distal tip as possible. Various methods and devices are available for crimping the valve prosthesis onto the catheter's distal tip, which may include hand-held devices or tabletop devices, for example. These crimping devices can initially provide an opening that is large enough to accommodate a valve prosthesis in its expanded condition and be positioned over a desired section of a distal tip of the catheter assembly. The valve prosthesis can then be compressed by reconfiguring the opening of the crimping device to uniformly decrease the size of the opening until the valve is compressed to the desired size. Due to the bioprosthetic valve, the valve prosthesis often is not shipped loaded into the delivery catheter. Instead, many trancatheter valve prostheses must be loaded into the catheter assembly by hand at the treatment facility (e.g., operating room) immediately prior to performance of the procedure.
Many transcatheter valve prostheses and corresponding catheter assemblies have connection or attachment points that the user/loader must ensure are connected during the loading procedure. If the connection points are not properly connected, there is a risk of premature detachment of the valve prosthesis from the catheter assembly. The user/loader may also need to observe that certain portions of the valve prosthesis are properly loaded into the catheter assembly. The connection points and other portions of the valve prosthesis which need to be observed during loading may be located at several locations around the circumference of the catheter assembly. For example, two connection points where the proximal (outflow) end of the valve prosthesis is connected to the catheter assembly may be disposed on opposite sides of the valve prosthesis. Further, the valve prosthesis is normally loaded in a liquid solution such as, but not limited to, a saline solution. Thus, a loading tray filled with such a liquid solution is often used for loading a valve prosthesis on a catheter assembly. The catheter assembly in some cases may be held in place by the loading tray or other devices while loading the valve prosthesis. Thus, in order to ensure that the connections and/or other observations on opposite sides of the catheter assembly are properly connected/observed, the catheter assembly and valve prosthesis must either be lifted out of the liquid solution and twisted, or the loader must try to make the connections without seeing all of the connections. Removing the valve prosthesis and catheter assembly out of the liquid solution during loading may introduce unwanted air bubbles into the assembly. Further, twisting the catheter assembly may damage the catheter assembly or the valve prosthesis.
According, there is a need for a device that allows the loader to observe all sides of the catheter assembly and prosthetic valve during loading of the prosthetic valve onto the catheter assembly.